<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>重复声明</title>
	</head>
	<body>
		<script>
			var a = 1;
			var a = 3;
			
			//let不能重复定义
			let b = 3;
			let b = 4;
			
			//const不能重复定义,不能重新赋值,是常量
			const c = 4;
			const c = 5;
			
			
		</script>
	</body>
</html>
